(WIRED) -- Research In Motion is preparing to release its much-awaited response to the iPad, the BlackBerry PlayBook tablet, a month behind schedule.

Among other reasons, Adobe Flash is probably contributing to the delay.

The PlayBook was supposed to be out the first quarter of 2011 but is now set to release April 19.

Some publications speculated on Thursday that the PlayBook's late launch is related to touchscreen supply. The PlayBook also lacks a finished software development kit for making apps, and won't have native mail, messaging and contacts apps.

Difficulty getting Flash to work properly on the PlayBook is probably another one of RIM's woes.

Let's take a look at the evidence. First, other tablet makers have had trouble with Flash. Motorola's Xoom launched without it, despite the fact that Motorola highlighted Flash support as a key feature.

RIM officials at the time were tight-lipped about the tablet's expected battery life, saying only that it would be more than an hour. That was an early version of the tablet, but choppiness in one of its key features doesn't bode well.

Last year RIM drummed up Flash support for the upcoming PlayBook, saying that it was going to deliver the full internet experience. That would, in theory, give the PlayBook an edge over the iPad.

"We're not trying to dumb down the internet for a small mobile device," says Mike Lazaridis, RIM's CEO, during the PlayBook demonstration. "What we're trying to do is bring up the performance and capability of the mobile device to the internet."